Gold Nanocluster Probe-Based Electron-Transfer-Mediated Electrochemiluminescence Sensing Strategy for an Ultrasensitive Copper Ion Detection

Abstract

Exploration of a novel and efficient sensing mechanism of Au nanocluster (AuNC)-based electrochemiluminescence (ECL) sensors is still a great challenge and opportunity for further applications. Herein, we proposed that the electron transfer (ET) could be used as a novel sensing regulation factor for the construction of an ECL-sensing platform based on the AuNC probe. As a proof-of-concept, the ECL quenching effect and mechanism of Cu2+ on pre-oxidation-treated l-methionine-capped AuNCs (OM-AuNCs) was investigated in detail. The results revealed that after the electrochemical excitation of the AuNC probe, the electron is transferred from the highest occupied molecular orbital (HOMO) of Met-Cu2+ to that of the OM-AuNCs, along with the ET from lowest-unoccupied molecular orbital (LUMO) of the OM-AuNCs back to the HOMO of Met-Cu2+, leading to the ECL quenching of OM-AuNCs. Since the ECL intensity of OM-AuNCs is sensitively affected by the ET process, a preferable linear dependence was obtained in the concentration range from 1.0 × 10–18 to 1.0 × 10–14 M with high selectivity. More importantly, a record low detection limit (LOD, 2.3 × 10–20 M) at the single copper ion level has been realized without any other amplification technique. Furthermore, the actual sample detection for Cu2+ exhibited satisfactory results. Therefore, this study enriches an ET-mediated ECL application and promotes a more rational design of ECL sensors.

Metal Nanoclusters in Point-of-Care Sensing and Biosensing Applications

“…According to the results, an electron flows in a circle between Cu 2+ and AuNCs so that the excited state AuNCs go back into the ground state leading the ECL to be quenched. The method presented a LOD of 2.3 × 10 –20 M for Cu 2+ ions …”

“…The method presented a LOD of 2.3 × 10 −20 M for Cu 2+ ions. 225 3.1.5.4. Coreaction Accelerated Electrochemiluminescence.…”

Energy Level Engineering in Gold Nanoclusters for Exceptionally Bright NIR Electrochemiluminescence at a Low Trigger Potential

“…Among them, electrochemiluminescence (ECL), a widely used light radiation energy output converted from electrochemical excitation, has evoked increasing interest for decades and becomes a powerful tool with precise temporal and spatial controllability, near-zero backgrounds, and a wide dynamic range. − ECL relies on electron transfer reactions between the electrochemically generated highly reactive radical intermediates on an electrode surface. Thus, electron transfer reactions between emitters and the coreactants are critical to regulate the excitation efficiency and ECL trigger potential in coreactant-pathway ECL systems. − To date, various strategies have been developed to improve the above reactions, such as interparticle charge tansport, electrocatalysis, , and intrareticular charge transfer-mediated competitive oxidation . Nevertheless, most discussion was only at the phenomenological level, while a deeper intrinsic mechanism for ECL generation has yet to be elucidated.…”

Ratiometric detection of Cu2+ in water and drinks using Tb(iii)-functionalized UiO-66-type metal–organic frameworks

“…A great deal of work has been invested in the detection of copper ions in view of the significant risks they pose to human health, ecosystems and food safety. 4,5…”

“…A great deal of work has been invested in the detection of copper ions in view of the signicant risks they pose to human health, ecosystems and food safety. 4,5 In the detection of copper ions, although traditional large instrumental methods (atomic absorption spectroscopy, high-performance liquid chromatography, inductively coupled plasma optical emission spectrometry, inductively coupled plasma-mass spectrometry, X-ray uorescence spectrometry, etc.) are sensitive and accurate, it is difficult to promote them due to their expensive instrumentation, complex operation, time-consuming nature and need for professional operators.…”